The aim of this study was to examine the positive relationship between religiosity and fertility from theperspective of perceived consequences of parenthood. Previous studies in Germany have found that highlyreligious people ascribe higher benefits and lower costs to having children. Furthermore, the impact ofcosts and benefits on fertility is less pronounced among the highly religious. This study tested these mech-anisms for fertility intentions and in the context of Poland–a country with a low fertility rate and highreligiosity in comparison to other European countries. A sample of 4892 men and women of childbearingage from the second wave of the Polish version of the Generations and Gender Survey conducted in 2014/2015 was used. First, the extent to which perceived costs and benefits mediate the impact of religiosity onfertility intentions was analysed. Second, whether religiosity moderates the impact of perceived costs andbenefits on fertility intentions was investigated. The results show that part of the positive effect of religiosityon fertility intentions can be explained by more-religious people seeing higher benefits of having children.Furthermore, but only in the case of women, religiosity moderates the impact of perceived costs on fertilityintentions, suggesting that the effect of perceived costs decreases with increasing religiosity.